As a conventional electrical connecting apparatus of this kind, an electrical connecting apparatus having a probe base plate in which a plurality of probes are provided and enabling adjustment of the flatness of the probe base plate has been proposed (See Patent Literature 1). This electrical connecting apparatus can act pressure or tensile force from a supporting member supporting the probe base plate on a central portion of the probe base plate. Even if a bend is produced in the probe base plate, the bending deformation of the probe base plate can be modified by the adjustment of this action, thereby maintaining the flatness of the probe base plate.
In producing a probe base plate in which a plurality of probes are provided, therefore, even if a bending deformation is produced in the probe base plate, the above-mentioned adjusting work after attaching the probe base plate to the supporting member enables to keep the probe base plate flat, so that the multiple probe tips extending from the probe base plate can be maintained on the same plane. This enables all the probe tips to surely contact an electrical connecting terminal corresponding to each of the above-mentioned probes of the electric circuit of the device under test, thereby obtaining a favorable electrical contact therebetween.
According to the conventional art described in Patent Literature 1, however, it is necessary to adjust so that all the probe tips may be positioned on the same plane according to the bending deformation introduced into each probe base plate every time the probe base plate is attached to the supporting member. The work of adjusting to make all the probe tips contact properly each corresponding electrical connecting terminal of the device under test in a state where the probe base plate is attached to the supporting member is complicated and requires skill. Particularly, in testing of numerous integrated circuits formed on a semiconductor wafer, since the number of probes provided on the probe base plate remarkably increases, it is difficult to adjust to make such numerous probes contact properly each corresponding pad on the semiconductor wafer. Also, when the probe base plate is enlarged along with enlargement trend of the device under test, adjustment of only the central portion of the probe base plate cannot deal with the trend. Further, the adjustability causes a problem in maintaining the flatness of the probe base plate in a stable manner, which makes the flatness of the probe base plate unstable as time passes.
Under such circumstances, the present applicant proposed in a previous international patent application (PCT/JP2005/009812) an electrical connecting apparatus accomplishing sure electrical connection between a probe and a corresponding electrical connecting terminal of an electric circuit of a device under test without the need for a flatness adjusting work of a probe base plate after being attached to a supporting member regardless of deformation of the probe base plate.
In this electrical connecting apparatus, probes are formed on a probe base plate with bending deformation in a free state without load so that the probe tips may be aligned on the same plane. Between the mounting plane of the supporting member and the probe base plate is arranged a spacer permitting a mounting bolt to be inserted therein, and this spacer acts to maintain the aforementioned deformation of the probe base plate at the time of tightening the mounting bolt. Thus, since the probe base plate is attached to the reference plane of the supporting member in a state of maintaining the aforementioned deformation, all the probe tips are positioned on the same plane.
Accordingly, after the probe base plate is attached to the supporting member, all the probe tips can be thrust to the respective electrical connecting terminals of the electric circuit of the device under test approximately uniformly without the need for the conventional adjusting work for flatness of the probe base plate. Despite the enlargement trend of the probe base plate, the aforementioned conventional troublesome flatness adjusting work is not needed per replacement of the probe base plate in which the multiple probes are provided, which enables an efficient electrical test.
However, the aforementioned spacer is arranged with its one end abutting on the underside of the supporting member and with its lower end abutting on the upper face of a securing portion formed on the probe base plate. Accordingly, when an electrical connecting apparatus is to be assembled by combining a supporting plate with a wiring base plate, etc., the spacer cannot be inserted into the supporting plate from the upper side of the supporting plate but needs to be inserted from the lower side of the wiring base plate through an inserting hole formed in the wiring base plate into the wiring base plate from the lower side thereof so that the upper end of the spacer may abut on the underside of the supporting member. After the spacer is arranged in this manner, the tightening bolt needs to be inserted from the upper face side of the supporting member so as to penetrate the supporting member and the spacer, and its tip end needs to be screwed in a screw hole formed at the top portion of the securing portion of the probe base plate.
In this manner, the spacer will not be inserted into an inserting hole of the tightening bolt of the supporting member, but the spacer needs to be held on the opposite side of the bolt inserting side of the supporting member so that the tightening bolt may pass through the inserting hole of the wiring base plate and the spacer when the tightening bolt is made to pass through the inserting hole of the supporting member. Thus, in a case where the operator selects a wrong spacer and thus needs to replace the wrong spacer with one with proper length, for example, it takes time to redo the work.
Patent Literature 1: Japanese National Patent Appln. Public Disclosure No. 2003-528459